Aminoplast resins and coating compositions containing same



compositions.

AMlNOPLAST RESINS AND COATING COMPO- SITIONS CONTAINING SAME No Drawing. Filed Dec. 4, 1957, Ser. No. 700,533

16 Claims. 01. 260-21) This invention relates to novel aminoplast resins which are particularly suitable for use in protective coating More particularly, the invention relates to etherified co-condensation products of melamine, an

,N-substituted melamine of the group consisting of N,N'-

dialkylmelamines, N,N',N"-trialkylmelamines and mixtures thereof and formaldehyde. The invention further relates to protective coating compositions containing such novel aminoplast resins.

V BACKGROUND OF THE INVENTION .Etherified melamine-formaldehyde resins have utility in many industrial fields including the protective coating arts. In particular, protective coating compositions containing blends of such etherified melamine-formaldehyde resins and oil-modified alkyd resins have been widely used as baking enamels. Such protective coating compositions have the desirable characteristics of moderately rapid cure, good color retention and good chemical resistance. However, the etherified melamine-formaldehyde resins have limited compatibility with the oilmodified alkyd resins and impair the gloss of the ultimate coatings when used in substantial quantities to eifect the maximum improvement in other film properties. The compatibility of etherified melamine-formaldehyde resins With oil-modified alkyd resins can be improved by modifying the etherified melamine-formaldehyde resins With other compounds such as arylsulfonamides. Such modification of the etherified melamine-formaldehyde resins, while improving the resins compatibility with oil-modified alkyd resins, adversely affects other properties of the protective coating compositions, particularly the rate of cure. Thus, in preparing protective coating compositions containing an etherified melamine-formaldehyde resin, the art must choose between formulations having fast cures and low gloss or formulations having good gloss, but slow cures and low detergent resistance.

Accordingly, it is an object of this invention to provide novel aminoplast resins having improved properties.

Another object of the invention is to provide novel aminoplast resins which are particularly suitable for use in protective coating compositions.

'Afurther object of the invention is to provide novel aminoplast resins which are compatible with oil-modified alkyd resins of all oil lengths.

Yet another object of the invention is to provide protective coating compositions containing novel aminoplast resms.

Other objects and advantages of the invention will be apparent from the following detailed descriptions thereof.

SUMMARY OF THE INVENTION "reaction product of at least 4 mols of a monohydric alco- United States Patent 2,957,835 Patented Oct. 25, 1960 ice hol containing 1-6 carbon atoms and a co-condensation product of 1 mol of melamine, 0.02-1.0 mol of an N-substituted melamine of the group consisting of N,N'-dialkylmelamines, N,N',N-trialkylmelam ines and mixtures thereof and at least 4 mols of formaldehyde. In another embodiment of the invention there are provided novel protective coating compositions which contain an aminoplast resin of the type described above and an oil-modified alkyd resin. The invention further relates to protective coating compositions containing (1) an aminoplast resin of the type described above, (2) an etherified melamine formaldehyde resin, and (3) an oil-modified alkyd resin.

EXPERIMENTAL The following examples are set forth to illustrate more clearly the principle and practice of this invention to those skilled in the art. Unless otherwise stated, where quantities are mentioned they are parts by weight.

Example I Reactants consisting of 126 parts (1 mol) of melamine, 17 parts (0.1 mol) of N,N,N-trimethylmela mine, 510 parts (6.3 mols) of formalin (37% formaldehyde), 600 parts (8 mols) of n-butanol and 4 parts of a 5% aqueous NaOH solution are charged to a reaction vessel equipped with a stirrer and a condenser that is fitted with a decanting esterification head. The alkaline solution (pH=l0.5) is refluxed for 1.0 hour with all of the condensate being returned to the reaction flask.

After adjusting the pH of the system to 6.4 with oxalic acid, the reaction mixture is again heated to reflux. During this phase of the reaction, the decanting head is set to continuously remove the water phase which separates in the distillation head and to return the butanol phase to the reaction flask. A total of about 300 parts of water phase is removed over a 5-hour period. The balance of the water remaining in the reaction mixture is removed by refluxing the reaction mixture with the esterification head being set for total takeofl. The distillation is continued until the boiling point of the distillate rises to 108 C., this step requiring about 0.5 hour. As the distillate is removed, an equivalent quantity of dry butanol is continuously added to the reaction flask. After cooling, the butanol is removed by vacuum distillation and the resin is recovered as a heavy viscous liquid.

Examples II-VI Five resins are prepared by the procedure of Example I except that the N,N',N"-trimethylmelamine is replaced with a stoichiometrically equivalent quantity of 5 different N-alkyl substituted melamines as indicated in Table I.

TABLE I N,N,N-tri-n-butalrnelarnine.

N,N,N"-tri-tert-butylmelamine.

N,l\ T,N-tri-(1,1,3,3-tetramethylbuty1) melamine.

N,N',N"-tri-sec-butylmelamine.

Example VII Example I is repeated except that the quantity of N,N',N"-trirnethylmelamine charged to the initial reaction is increased to 34 parts (0.2 mol) and the quantity of formalin charged is increased to534 parts (6.6 mols). The resin is obtained as a thick viscous liquid,

Examples VIII-XII Five resins are prepared by the procedure of Example VII except that the N,N,N"-trimethylmelarnine is replaced with a stoichiometrically equivalent quantity of 5 different N-alkyl melamines as indicated in Table II.

TABLE II Example N-Substitutcd Melamine Employed N,N ,N-tri-n-butylmelamine.

N ,N ,N '-tri-sec-butylmelamine.

N,N,N-tri(l,1,3,3-tetramethylbutyl)melamine.

N,N-dimethyl-N-o ctadecylmela-mine.

Example XIII Example I is repeated except that isobutanol is employed in lieu of n-butanol.

Example XV Example XIII is repeated except that isobutanol is employed in lieu of n-butanol.

Example XVI Example I is repeated except that 24 parts (0.1 mol) of N,N,-di-tert-butylmelamine are employed in lieu of the N,N,N"-trimethylmelamine.

Example XVII Example I is repeated except that a mixture of 36 parts (0.15 mol) of N,N'-di-tert-butylmelamine and 37 parts (0.15 mol) of N,N',N"-triisopropylmelamine is employed in lieu of the N,N',N"-trimethy1melamine.

Example XVIII Example I is repeated except that the quantity of N,N',N-trimethylmelamine employed is reduced to 9 parts (0.05 mol).

Example XIX The following protective coating compositions are prepared in which the figures listed are parts by weight:

Coating Composition Component A B C D Control I Control II Resin Example I l0 Resin Example IL. Resin Example III. Resln Example IV 10 Prior Art Resin 1 10 Prior Art Rcs'mZ l0 Alkyd Resin-" 20 20 20 20 20 Titanium Diox 25 25 25 25 25 Butanol l0 l0 10 10 10 Xylol 35 35 35 35 35 35 The alkyd resin included in the above compositions consists of a blend of two parts of a glyceryl phthalate resin modified with 35 weight percent of coconut oil fatty acids and one part of a glyceryl phthalate resin modi- Prior art resin 2 included in control H is a commercially available butyl ether of a melamine-formaldehyde resin that is modified with 0.32 mol of toluene sulfonamide per mol of melamine.

A series of steel panels are spray coated with the above coating compositions and the films are cured by heating for, respectively, 30 minutes at 250 F. and 20 minutes at 300 F. The cured films are 2 mils thick. The Sward hardness of each of the films is measured. The detergent resistance of the films cured at 300 F. is measured by ASTM method D714-45 in which the panels are maintained in an 0.5% aqueous detergent solution for 118 hours at F. The results are set forth in Table III.

TABLE III Coating Composition Property- Sward Hardness A B O D Control Control I II Detergent Resistance... N. D. N. D. N. D. N. D. 1?.1. D. F.T.D.

Example XX Additional steel panels are spray coated with the coating compositions described in Example XIX. One series of the panels is cured for 20 minutes at 300 F. and a second series of the panels is baked for 16 hours at 300 F. The panels are examined visually and within each series the gloss obtained with the experimental coating compositions is at least equal to and in some cases superior to the gloss obtained from the two control compositions. These data establish that the initial gloss and the gloss retention on overbaking of the experimental coating compositions are fully equivalent to the two control coating compositions. This showing is highly significant, since the control compositions are considered by the art to be excellent with respect to these properties.

Example XXI The following protective coating composition is prepared:

Parts Component:

Alkyd resin 15.0 Resin of Example V 15.0 Titanium dioxide 15.0 Lampblack 0.2 Xylol 40.0 Butanol 15.0

The alkyd resin included in the above formulation is a glyceryl phthalate resin modified with about 42 weight percent of dehydrated castor oil fatty acids. The coating composition is sprayed onto a steel paneland baked for 20 minutes at 300 F. The resulting film is very hard and has high gloss and good detergent resistance.

Example XXII Thirteen unpigmented, clear baking varnishes are prepared by including each of the resins of Examples VI-XVIII in the following formulation:

The alkyd resin included in the formulation is a glyceryl phthalate resin modified with about 62 weight percent of soybean oil fatty acids. The hydrocarbon solvent is a commercial mixture of petroleum aliphatic hydrocarbons. The varnishes are sprayed onto steel panels and baked for 20 minutes at 300 F. to provide hard films having high gloss and good detergent resistance.

Example XXIII A protective coating composition of good properties is .obtained with the following formulation:

Component: .Parts Alkyd resin 20 Resin of Example I 6 Butyl ether of a melamine-formaldehyde resin 4.

Titanium dioxide 25 Butanol Xylol 40 The alkyd resin employed is described in Example XIX and the butyl ether of the melamine-formaldehyde resinis prior art resin 1 described in Example XIX.

DISCUSSION The aminoplast resins of this invention are the etherified reaction product of at least 4 mols of a monohydric alcohol'containing 1-6 carbon atoms and a co-condensation product of 1 mol of melamine, 0.02-1.0 mol'of an N-substituted melamine of the group consisting of N,N- dialkylmelamines, N,N,N"-trialkylmelamines and mixtures thereof, and at least 4 mols of formaldehyde. In a preferred embodiment of the invention, the aminoplast resins are the etherified reaction product of a butanol and either (1) a co-condensation product of melamine, an N,N,N"-tri-sec-alkylmelamine and formaldehyde or (2) a co-condensation product of melamine, an N,N'-di" tert-alkylmelamine and formaldehyde.

The co-condensates employed in the invention are prepared by heating the melamine, the N-substituted melamine and the formaldehyde under alkaline conditions,

' e.g., at a pH of 8.5-105, in a suitable solvent such as Water, a 1-6 carbon atom monohydric alcohol or a wateralcohol mixture. The quantity of N-substituted melamine employed is 0.02-1.0 or preferably 0.05-0.5 mol per mol of melamine. The minimum quantity of formaldehyde employed is at least 4 mols per mol of melamine, but preferably the formaldehyde is employed in a quantity sufficient to react with each of the reactive hydrogen i atoms contained in the melamine and the N-substituted melamine. In calculating the quantity of formaldehyde 7 to be employed, melamine contains 6 reactive hydrogen atoms, the N,N-dialkylmelamines contain 4 reactive hydrogen atoms and the N,N',N"-trialkylmelamines contain 3 reactive hydrogen atoms.

The alkyl groups contained in the N-substit-uted melamines included in the aminoplast resins of the present and preferably the alkyl constituents are selected so that the total number of carbon atoms contained in all of the alkyl groups does not exceed about 36. Typical N-substited melamines which may be employed include:

N,N'-diethylmelamine N,N-diisopropylmelamine N,N'-di-sec-amylmelamine N,N-di-sec-butylmelamine N,N'-di-tert-butylmelamine N,N-di( l,1,3,3-tetramethylbutyl) melamine N-isopropyl-N'-dodecylmelamine N-ethyl-N-octadecylmelamine N,N',N"-tri-sec-amylmelamine N,N',N"-tri-tert-amylmelamine N,N-dimethyl-N"-dodecylmelamine N,N'-diisopropy1- "-Z-ethylhexylmelamine 'The N-s-ubstituted melamines can be prepared by methods which are known in the art. For example, N,N'-dialklymelamines can be prepared by reacting 2 mols of an appropriate alkylamine with 2,4-dichloro-6-amino-striazine. Similarly, N,N',N"-trialkylmelamines can be prepared by reacting 3 mols of an appropriate alkylamine with cyanuric chloride. Alternatively, the N-substituted melamines can be prepared by the method disclosed in U.S. 2,361,823.

The etherified resins are prepared by heating the cocondensate of melamine, the N-substituted melamine and formaldehyde with at least 4 mols of a monohydricalcohol containing 1-6 or preferably 3-6 carbon atorns under acid conditions, e.g., at a pH of about 5.5-7.0. During this reaction, the co-condensation product is both etherifiedand polymerized. Thus, the alcohol functions as both a reactant and as a solvent for the reaction. Preferably, the reaction is carried out under reflux conditions (at either atmospheric or reduced pressure) so that Water may be removed from the reaction system by azeotropic distillation. To maintain the minimum quantity of alcohol required in'the reaction system when operating under reflux conditions, it is necessary to (1) return the distilled alcohol to the reaction system, or (2)'add alcohol to the reaction system as makeup, or (3) initially charge a large excess of alcohol to the reaction. Essentially any 1-6 carbon atom monohydric alcohol such as methanol, ethanol, propanol or hexanol may be employed inthe etherification reaction. The alcohol employed will be influencedto a large degree by the use that is to be made of the resin. Where the resin is to be employed in protective coating compositions, it is preferred to use n-butanol or especially isobutanol for this purpose. When isobutanol is employed as the etherifying alcohol, the pH of the system during the etherification reaction must be maintained within the limits of about 5.8-7.0 or preferably 6.0-6.5. After the etherification reaction is complete, the resin solution may be concentrated to the desired solids level or recovered in solvent-free form by removing the solvent alcohol by vacuum distillation.

The resins of the invention may be used in the manufacture of textile printing pastes, as an ingredient in adhesive formulations, and in the resin finishing of textiles (especially cottons) e.g., by methods analogous to those disclosed in US. 2,661,262 and U.S. 2,661,313, etc. The resins also may be used per se or in conjunction with other film-forming resins in the preparation of protective coating compositions.

The present invention is also concerned with protective coating compositions which contain as the film-forming polymers a binary mixture of an aminoplast resin of the type herein described and an oil-modified alkyd resin. The novel aminoplast resins are compatible with alkyd resins of all oil lengths in virtually all proportions. Preferably, however, the resinous components of the coating compositions of primary concern consist of 10-50 weight -50 weight percent of the oil-modified alkyd resin.

The invention further relates to protective coating compositions which contain as the film-forming polymers a ternary mixture of (1) an oil-modified alkyd resin, (2) a novel aminoplast resin of the type herein described, and (3) an etherified melamine-formaldehyde resin. The oil-modified alkyd resin ordinarily will constitute 50-90 weight percent of the total of the 3 film-forming polymers. The novel arninoplast resin in turn ordinarily will constitute at least 20 weight percent and preferably 20-75 weight percent of the binary mixture of the novel aminoplast resin and the etherified melamine=formaldehyde resin.

The etherified melamine-formaldehyde resins included in the protective coating compositions described in the paragraph above are known in the art. Chemically, these resins are the etherified reaction product of at least 4 mols of a monohydric alcohol containing 1-6 or preferably 3-6 carbon atoms and a condensation product of 1 mol of melamine and at least 3 mols of formaldehyde. Preferably, the monohydric alcohol employed to etherify the melamine-formaldehyde condensate is a butanol such as n-butanol or isobutanol. If desired, the etherified melamine-formaldehyde resin may be modified with minor amounts of other compounds containing amino hydrogen atoms, e.g., an arylsulfonamide.

The alkyd resins included in the protective coating compositions of the invention are condensates of polyhydric alcohols such as glycols, glycerol, sorb-itol, pentaerythritol, etc. with polybasic acids or anhydrides thereof, e.g., phthalic acid, phthalic anhydride, isophthalic acid, fumaric acid, maleic acid, maleic anhydride', adipic acid, azelaic acid, etc. These alkyd resins are modified with drying, semi-drying and non-drying oils such as coconut oil, castor oil, dehydrated castor oil, soybean oil, linseed oil, tung oil, or the acids and glycerides derived therefrom. The oil-modified alkyd resins having the best balance of properties for inclusion in the protective coating compositions of the invention contain 30-70 and preferably 30-40 weight percent of combined fatty acids. As is known, such acids contain about 12-20 carbon atoms.

The protective coating compositions of interest ordinarily will comprise 20-70% of the mixture of the aminoplast resin (or resins), and the oil-modified alkyd resin dissolved in a suitable organic solvent such as hydrocarbons, alcohols, ethers, ketones, esters, and mixtures thereof, e.g., xylol-butanol and aliphatic hydrocarbonbutanol mixtures. Pigments, driers and other convent1onal ingredients may be included in the coating comj-positio'ns. Such compositions usually will be formulated to have a total solids content of about 40-60%.

The coating compositions of the invention may be advantageously employed to protect wooden, paper and metal surfaces. The coating compositions may be applied to the surfaces to be protected by conventional methods of application such as brushing, spraying, roll coating, dipping, etc. The films may be cured by heating for short periods of time at ISO-400 F.

The above descriptions and particularly the examples are set forth by Way of illustration only. Many other variations and modifications of the invention will be apparent to those skilled in the art and may be employed without departing from the spirit and scope of the invention herein described.

What is claimed is:

1. A resin comprising an etherified reaction product "of at least 4 mols of a monohydric acyclic alcohol contaming 1-6 carbon atoms and a co-condensation product of 1 mol of melamine, 0.02-1.0 mol of an N-substituted melamine and at least 4 mols of formaldehyde; said N- substituted melamine being selected from the group consisting of N,N-dialkylmelamines, N,N,N"-trialkylmelamines, and mixtures thereof, the individual alkyl groups of said N-substituted melamines being acyclic and contaming a maximum of about 20 carbon atoms, the total number of carbon atoms contained in all of said alkyl groups not exceeding about 36.

2. A resin comprising an etherified reaction product of at least 4 mols of a butanol of the group consisting of nbutanol, isobutanol and mixtures thereof and a co-condensation pro-duct of 1 mol of melamine, 0.02-1.0 mol of an N-substituted melamine and at least 4 mols of formaldehyde; said N-substituted melamine being selected from the group consisting of N,N-dialkylmelamines, N,N,N-tnialkylmelamines, and mixtures thereof, the individual alkyl groups of said N-substituted melamines being acyclic and containing a maximum of about 20 carbon atoms, the total number of carbon atoms contained in all of said alkyl groups not exceeding about 36.

3. A resin as in claim 2 wherein the N-substituted melamine included in the co-condensation product is an N,N'-di-tert-alkylrnelamine.

4. A resin as in claim 2 wherein the N-substituted melamine included in the co-condensation product is an N,N',N"-tri-sec-alkylmelamine.

5. A resin as in claim 2 wherein the N-substituted melamine included in the co-condensation product is N,N',N"-trimethylmelamine.

6. A resin as in claim 2 wherein the N-substituted melamine included in the cocondensation product is N,N',N"-tri-n-butylmelamine.

7. A resin as in claim 2 wherein the N-substituted melamine included in the co-condensation product is N,N,N"-tri-tert-butylmelamine.

8. A resin as in claim 2 wherein the N-substituted melamine included in the co-condensation product is N,N',N-tri( 1,1,3 ,3 -tetramethylbutyl melamine.

9. A resin as in claim 2 wherein the N-substituted melamine included in the co-condensation product is N,N"-di-tert-butyl-melamine.

10. A process for preparing a resin which comprises heating 1 mol of melamine, 0.021.0 mol of an N-substituted melamine and at least 4 mols of formaldehyde in an aqueous medium under alkaline conditions to cocondense said reactants and then etherifying said co-condensation product by heating said co-condensation product and at least 4 mols of a monohydric acyclic alcohol containing 1-6 carbon atoms to substantially atmospheric reflux temperature under acidic conditions; said N-substituted melamine being selected from the group consisting of N,N'-dialkylmelamines, N,N',N"-trialkylmelamines and mixtures thereof, the individual alkyl groups of said N-substituted melamines being acyclic and containing a maximum of about 20 carbon atoms, the total number of carbon atoms contained in all of said alkyl groups not exceeding about 36.

IL A process for preparing a resin which comprises heating 1 mol of melamine, 0.021.0 mol, of an N-substituted melamine and at least 4 mols of formaldehyde in an aqueous medium under alkaline condition to co-condense said reactants and then etherifying said co-cendensation product by heating said co-condensation product with at least 4 mols of a butanol of the group consisting of n-butanol, isobutanol and mixtures thereof to substantially atmospheric reflux temperature while maintaining the pH of the solution in the range of 5.5-7.0; said N-substituted melamine being selected from the group consisting of N,N'-dialkylmelamines. N.N',N-trialkylmelamines and mixtures thereof, the individual alkyl groups of said N-substituted melamines be'ng acyclic and containing a maximum of about 20 carbon atoms, the total number of carbon atoms contained in all of said alkyl groups not exceeding about 36.

12. A process for preparing a resin which comprises heating 1 mol of melamine, 0.02-l.0 mol of an N-substituted melamine and at least 4 mols of formaldehyde in an aqueous medium under alkaline conditions to cocondense said reactants and then etherifying said co-condensation. product by heating said co-condensation prodl 9 and at least 4 mols of isobutanol to substantially atmospheric reflux temperature while maintaining the pH of the solution in the range of .87.0; said N-substituted melamine being selected from the group consisting of N,N'-dialkylmelamines, N,N',N-trialkylmelamines and mixtures thereof, the individual alkyl groups of said N-substituted melamines being acyclic and containing a maximum of about 20 carbon atoms, the total number of carbon atoms contained in all of said alkyl groups not exceeding about 36.

13. A protective coating composition comprising an organic solvent solution of a mixture of an oil-modified alkyd resin and an etherified reaction product of at least 4 mols of a monohydric acyclic alcohol containing 1-6 carbon atoms and a co-condensation product of 1 mol of melamine, 0.02-1.0 mol of an N-substituted melamine and at least 4 mols of formaldehyde; said N-substituted melamine being selected from the group consisting of N,N-dialkylmelamines, N,N',N"-trialkylmelamines and mixtures thereof, the individual alkyl groups of said N-substituted melamines being acyclic and containing a maximum of about 20 carbon atoms, the total number of carbon atoms contained in all of said alkyl groups not exceeding about 36.

14. A protective coating composition comprising an organic solvent solution of a mixture of 5090 weight percent of an oil-modified alkyd resin and, correspond ingly, 50-10 weight percent of an etherified reaction product of at least 4 mols of a butanol of the group consisting of n-butanol, isobutanol and mixtures thereof and a cocondensation product of 1 mol of melamine, 0.02-1.0 mol of an N-substituted melamine and at least 4 mols of formaldehyde; said N-substituted melamine being selected from the group consisting of N,N'-dialkylmelamines, N,N',N"-trialkylmelamines and mixtures thereof, the individual alkyl groups of said N-substituted melamines being acyclic and containing a maximum of about 20 carbon atoms, the total number of carbon atoms contained in all of said alkyl groups not exceeding about 36.

15. A protective coating composition comprising an organic solvent solution of a ternary mixture of (1) an oil-modified alkyd resin, (2) an etherified reaction product of at least 4 mols of a monohydric acyclic alcohol containing 1-6 carbon atoms and a co-condensation product of 1 mol of melamine, 0.021.0 mol of an N-substituted melamine of the group consisting of N,N'-dialkylmelamines, N,N,N"-trialkylmelamines and mixtures thereof, the individual alkyl groups of said N-substituted melamines being acyclic and containing a maximum of about 20 carbon atoms, the total number of carbon atoms contained in all of said alkyl groups not exceeding about 36, and at least 4 mols of formaldehyde, and (3) an etherified reaction product of at least 4 mols of a monohydric acyclic alcohol containing l-6 carbon atoms and a condensation product of 1 mol of melamine and at least 3 mols of formaldehyde; said oil-modified alkyd resin constituting -90 weight percent of the total of (1), (2) and (3); said component (2) constituting at least 20 weight percent of the total of (2) and (3).

16. A protective coating composition comprising an organic solvent solution of a ternary mixture of (1) an oil-modified alkyd resin, (2) an etherified reaction product of at least 4 mols of a butanol of the group consisting of n-butanol, isobutanol, and mixtures thereof and a co-condensation product of 1 mol of melamine, 0.021.0 mol of an N-substituted melamine of the group consisting of N,N'-dialkylmelamines, N,N',N"-trialkylmelamines and mixtures thereof, the individual alkyl groups of said N-substituted melamines being acyclic and containing a maximum of about 20 carbon atoms, the total number of carbon atoms contained in all of said alkyl groups not exceeding about 36, and at least 4 mols of formaldehyde, and (3) an etherified reaction product of at least 4 mols of a butanol of the group consisting of n-butanol, isobutanol and mixtures thereof and a condensation product of 1 mol of melamine and at least 3 mols of formaldehyde; said oil-modified alkyd resin constituting 50-90 weight percent of the total of (1), (2) and (3); said component (2) constituting at least 20 weight percent of the total of (2) and (3).

References Cited in the file of this patent UNITED STATES PATENTS 2,197,357 Widmer Apr. 16, 1940 2,209,292 Berger July 23, 1940 2,222,350 Keller et a1 Nov. 19, 1940 2,294,590 West Sept. 1, 1942 2,361,823 DAlelio et al. Oct. 31, 1944 2,454,495 Widmer et al. Nov. 23, 1948 2,485,059 Mohrman et al. Oct. 18, 1949 2,809,954 Kazenas Oct. 15, 1957 OTHER REFERENCES Hodgins et al.: Melamine-Formaldehyde Film-Forming Compositions, Ind. & Eng. Chem., p. 769-779, vol. 33, No. 6.

UNITED STATES PATENT OFFICE CERTIFICATION OF CORRECTION Harry M Culbertson et a1 It is hereby certified that ent requiring correction and that corrected below.

error appears in the above numbered patthe said Letters Patent should read as Column 8, line 55, for "condition" read conditions line 56, for "c0cenden" read co-conden- Signed and sealed this 2nd day of May 1961.

(SEAL) Attest:

ERNEST W SWIDER DAVID Lo LADD Attesting Officer Commissioner of Patents 

1. A RESIN COMPRISING A ETHERIFIED REACTION PRODUCT OF AT LEAST 4 MOLS OF A MONOHYDRIC ACYCLIC ALCOHOL CONTAINING 1-6 CARBON ATOMS AND A CO-CONDENSATION PRODUCT OF 1 MOL OF MELAMINE, 0.02-1.0 MOL OF AN N-SUBSTITUTED MELAMINE AND AT LEAST 4 MOLS OF FORMALDEHYDE, SAID NSUBSTITUTED MELAMINE BEING SELECTED FROM THE GROUP CONSISTING OF N,N''-DIALKYLMELAMINES, N,N''N"-TRIALKYLMELAMINES, AND MIXTURES THEREOF, THE INDIVIDUAL ALKYL GROUPS OF SAID N-SUBSTITUTED MELAMINES BEING ACYCLIC AND CONTAINING A MAXIMUM OF ABOUT 20 CARBON ATOMS, AND TOTAL NUMBER OF CARBON ATOMS CONTAINED IN ALL OF SAID ALKYL GROUPS NOT EXCEEDING ABOUT
 36. 